Big Sister
by Kessy Rods
Summary: SuperTwins Series #1: After the whole Cadmus fiasco, Superman fled home - to talk to his daughter, Claire, and get some perspective of what to do with the boy who looks exactly like him. He should've expected her to act like this, really. # AU #
1. Getting Some Perspective

**Disclaimer: I do not own Young Justice or anything DC related. Or this would be canon. Which is not.**

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 **Notes: I have this on my mind for a long time, and decided to give it a shot. It's my first story in the YJ fandom, and please notice that I'm using the cartoon as a guide, since I haven't read the comics.**

 **Also, english is not my first language, so mistakes are bound to happen. If anyone wants to be a beta for this story (for which I'll be very grateful), send me a message!**

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 **Chapter 1 - Getting Some Perspective**

Clark was NOT expecting this when he woke up this morning. At all.

He supposed he should've seen it coming, sort of, since it was a long time since his enemies had done something so _wrong_. Not that they did anything right in the past. It's just... The idea of making a child and force-feed him "education" and growth... All because they wanted their personal Superman... Was so wrong that twisted Clark's guts in a painful way.

True, he had practically fled once Batman finished getting his explanations from the three trouble-makers that had freed _him_ ; but he really didn't know how to handle _this_. He needed to figure it out first, that's why he made an awful apology to the boy and fled.

He went home as soon as the Lanterns agreed to take Blockbuster to somewhere that could hold him, and was met with the smell of apple pie getting out of the oven.

He smiled, despite of his conflicted thoughts and feelings. She always knew when he need it.

"I'm home," he said out of habit, speeding into his room and rapidly changing into normal clothes and going to meet her in the kitchen.

"Hi dad," she gave him a very brief peck on the cheek and came back to the stove where she was mixing something. "I'm making a cake for tomorrow's school party. But after the sun-blocking thing, I thought you could want some pie, so I made it too."

"Thank you sweetie. You always know... Can I?"

"Sure. I got it out five minutes ago."

Clark served a piece to himself and sat on the chair by the counter, watching his daughter finish the cake and putting it in the oven.

"Is the pie good?" she asked, turning to look at him.

He took a moment to answer, concentrating on her features. The short black hair, the bright blue eyes...

Claire Martha Kent was product of a mistake in judgement he made when he was twenty years old. One college party, a friend with too much to drink flirting with him, and his heart broken for having lost the former love of his whole teenage life to another guy came all crashing down on him, and he slept with Marie, who three months later told him, in tears, that she was pregnant.

They didn't engage in a relationship, but Clark knew he had to take responsibility, or the child would be in danger. But short after Claire was born, Marie suffered a car accident, dying and leaving Claire - beautiful and still very vulnerable Claire - without a mother.

Clark made his damn best to raise his child. After he became Superman - she was only four at the time - even more so. Claire was a good girl, kind hearted and compassionate, and he couldn't be more proud of her if he tried. But she was also lonely.

Which led him to think about _the boy_.

"Dad?"

Apparently, he spent more than just a few seconds thinking.

"Are you okay?" she looked worried, and he tried a smile for her.

"I'm fine, sweetie," he said, although he didn't know if it was true. "I'm just tired."

"I bet." she started cleaning up the mess in the kitchen while talking. "It took how many Leaguers to stop that wizard?"

"Almost everyone." he said. "Canary and Green Arrow were busy with something else, but ended up getting there in the end."

Sighing, he finished his pie.

"Something is wrong." Claire said, cleverly so.

"What makes you think that?"

She looked at him with a face that cleary said ' _don't lie to me, dad_ '. He couldn't supress the smile looking at it.

"You are beyond tired. You're too quiet and there's this haunted look in your eyes that I don't like one bit. What happened?"

She demanded with a tone that left no space to argue, and Clark decided that she needed to know anyway. Maybe she even helped him think clearly about this, about what to do with the boy who was an exact copy of himself at the age of 16 that was somewhere with a Leaguer - probably Batman.

He sighed, and decided that it was best to tell her already. She had ways of always know what she wanted.

"After we stopped Wotan…" he started, noticing how she stopped everything to listen to what he had to say. "Batman became aware that the three sidekicks - Robin, Aqualad and Kid Flash - that were at the Hall of Justice, had left, even after he explicitly told them to stay."

She didn't said anything, allowing him to continue.

"He was furious, even more so after we realized that Cadmus' laboratories building had been destroyed, and their tracers were pointing they were there. The whole League went there to see what had happened and…"

He suddenly had his mouth dry. Claire frowned, confused, and Clark sighed and ran a hand through his hair.

"Cadmus had a small fire which we ignored after we heard about Wotan. The boys went there to investigate, since Batman was suspicious about it, and ended up finding out a lot of things, including a clone, made by Cadmus to eventually replace me."

Her expression became shocked. "What?"

"His name is Superboy," Clark sighed, more tired that he realized. "They freed him, and he helped them escape. Together, the four of them left Cadmus. But not before the scientist in charge transformed into a sort of monster to stop them, and they ended up destroying all the main building at the surface. We got there right after they got out of the rubble."

"Wow… I… Are they alright?"

"Yes, mostly unharmed. Just a few cuts and bruises, but…" He sighed again. "They decided that don't want to be treated as sidekicks anymore, and while Batman makes his mind about what to do with it… Superboy is at the League's custody."

Suddenly Claire was mad.

"At the _League_ 's custody? Why not yours, dad?"

"He is my clone, Claire. I just…"

"You couldn't take him?" she seemed pissed, for some reason. "I'm assuming he's a copy of you, physically."

"Yes."

"So he could be your son."

"... Yes."

"Then why not bring him home? To stay with us?"

Clark didn't have an answer for that. Claire looked tired, all of a sudden.

"Dad, I can only imagine how you feel after seeing that someone used your DNA to make a clone, but… He doesn't have anything to do with it."

That made him look at her puzzled. "What do you mean?"

"He didn't _asked_ to be made. It's not his fault. You can't blame him for other people's faults." she explained, slowly. "Please tell me you're going to reconsider that and talk to him properly."

"I can't promise you that."

She sighed and started to leave.

"I'm not going to force you to, dad. I just think you owe him at least the benefit of the doubt. He chose to leave Cadmus with the other three, so I'm guessing he didn't want to be Cadmus' lab pet anymore. That says something."

"What?" he asked, wanting to have some kind of revelation at Claire's words, but getting nowhere.

She looked at him with kindness and patience in her kryptonian-blue eyes.

"It says, at the very least, that he wants to be his own person. That he wants to live his own life, make his own decisions. It says that he wants to do what _Superman would do_."

He didn't have anything to reply to that, and with a quick kiss on his cheek, Claire went to her room, leaving Clark with his troubled thoughts alone.

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 **So, what do you think? Let me know if you found any mistakes and I'll edit it. (If you want to be a beta for this, send me a message).**

 **A new chapter later this week, hopefully. ;)**


	2. A (Not So Much) Tough Decision

**A/N: Thought I would take longer to write this, but I was wrong, so... Early chapter! Enjoy.**

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 **Chapter 2 - A (Not So Much) Tough Decision**

The next day, Clark found Claire packing her things for school early. One hour early.

"Isn't a little bit early for school, Claire?"

She didn't even look up from where she was in the kitchen, putting her cake on a proper place to carry.

"I have to get there a little earlier today. To set everything up for the party."

"What kind of party is it, anyway?" he asked, moving to the coffee machine so he could also start his day.

"It's a surprise party for one of our favorite teachers, Mrs. Anderson."

He nods, and the two stay in silence even after Claire finishes packing everything and starts to eat the pancakes she made for breakfast.

Finally, after they are finishing with the dishes - Ma had taught her never to leave a mess - she decided to talk about the elephant in the room.

"So… Thought about what you're going to do with Superboy?"

Her voice sounded apreensive, for some reason. Uncertain. He didn't like that; it didn't suit his fierce and strong daughter. Clark turned to look at her properly.

"Kind of…" he had, honestly.

He spent almost half the time he had to sleep thinking about what to do with the clone and how could he overlook what he was and what he was made for. He still wasn't happy with the decision, but looking at Claire now… He knew it was the right one.

"And?" she pressed, biting her lower lip.

He sighed and ran a hand through his hair.

"I'm gonna call Batman and talk to him about that. And if it's okay… I will bring him home later."

Her eyes lit up at that, what only made him more sure about his decision. If she was that happy, maybe things could work out for him and Superboy in the end.

"That's wonderful!" she cheered while both of them went to the hallway, in the way of their bathrooms. "Please tell me beforehand, though. I want to make something to welcome him properly if he comes today."

He laughed a litte. He should've expected that she would act this way. All happy and boucing and eager to have a brother.

"You bet." he said.

A couple minutes later, he bid her farewell and she went to school. It was still early for him to go do the Planet, and he wasn't much in the mood for being yelled at so soon in the day by Lois or Perry, so he picked up his comm. unit and called Batman.

His gruff voice sounded not much after.

" _Batman_."

"I need to talk to you," he said without much else. He knew how the Bat was grumpy by day.

" _Is it urgent?_ "

"Kind of… It's about Superboy."

A moment of silence, and then, more slowly, " _What about him?_ "

He sighed. "Can we meet at the Watchtower? I would rather have this conversation personally. And there's a lot to consider and talk about."

Another moment, and he heard Bruce sighing.

" _I have an early meeting now. But I'll be free by lunch. We can meet then._ "

"Ok, it works for me. Call me when you're free and I'll go there."

" _Fine_."

And without much else, he hung up. Typical Bruce, so Clark wasn't shocked. He look at his clock and realized he still had a lot of time before he needed to go to work, so he decided he should end this soon, and picked up the phone, pressing the numbers to his parents' house in Kansas.

He had a very distinctive feeling that Ma and Pa would be as happy as Claire hearing the news.

And he was absolutely right.

They were delighted to have a new 'grandson' – as Ma kept calling Superboy – and started to make plans for the next family dinner – which would have to be soon, considering Ma's enthusiasm.

Clark didn't talk much about it, and soon they realized that he was a little hesitant to bring Superboy into their lives. They eased his mind reminding him that he was also adopted, so why couldn't he adopt a new son?

" _It will be so good for you, Clark,_ " Ma was saying, with a soothing voice. " _He may have been created for a purpose, but he is his own person now. His destiny is not set in stone. And you can teach him so much!_ "

He stayed silent, only giving a few hums as his mother kept talking.

" _Your mother and daughter are right, son,_ " his father intervened. " _You have to give this boy the benefit of the doubt. Meet him. Take care of him. Show him you care. I bet he only wants to have your approval now that he's out of that lab. Think about that._ "

After promising he would think, they hung up, and after a few more minutes debating wheter or not go to work earlier, Clark eventually went to the shower, officially starting his day.

~.~

The morning was absolutely uneventful, with Clark just sitting on his desk finishing up a few stories he had to deliver. And proofreading Lois' work, of course.

When his time for lunch arrived, Clark left the building and went to a diner close by to eat something while waiting for Bruce to inform him he was free. It didn't take long. As soon as he finished his sandwich, his comm. buzzed.

" _I'm going to the Watchtower now._ " came the low voice of the Batman.

He whispered on his comm., knowing the advanced technology would pick what he was saying with no problems.

"I'm on my way."

The buzz was cut off, and Clark finished his launch and paid, walking to the alley two blocks from there, were a zeta tube was hidden. He speed-changed into his Superman suit and got in, soon being transported to the Justice League's orbiting satellite and headquarters.

 **Recognized: Superman; 01**.

The robotic voice annoucing his arrival was monotone, and he found Batman waiting for him by the portals with his arms crossed.

"I only have twenty minutes." the other hero said.

"Ok." he frowned. No time for stalling the conversation, then. Too bad.

The two of them walked 'til the nearest conference room, and as soon as they were both inside, Clark sighed and went to the point.

"I told Claire about Superboy." he confessed.

He could see the smallest of smirks in Batman's lips, something that only the people who knew him better knew how to see. And something only his daughter could get that easily. Without even being present.

"And I assume she gave you an ultimatum."

He sat on a chair nearby, Batman mimicking him in another chair across from him.

"Pretty much." he admitted. "But she also made me see that I'm blaming him for other people's actions, and this is not right."

"And she wants a brother." Bruce deadpanned.

"That too." Superman couldn't help the smile remembering her enthusiasm earlier.

"I was thinking about telling her myself if you didn't." Batman admitted. "I knew she would put some sense into you."

Superman frowned. "What do you mean?"

His friend sighed and uncrossed his arms, "Superboy was very disappointed you didn't stayed yesterday. Robin said they promised him to introduce him to you, and he was looking forward to it. And then you barely acknowledged him. How do you think he felt?"

Superman grimaced. "I didn't know what to do."

"So your first action was to run away?" Batman's voice was stern and left no space for apologies, and Clark sighed, defeated.

"I admit, I was a complete disaster yesterday. But I want to make things right. He's just a boy, in the end."

"And as your daughter so cleverly said it, it's not his fault he was made by your enemies. We can deal with them later, without involving him."

"We?"

"The League."

Superman nodded.

"Now, I assume you did tests on Superboy to see if he was safe?"

Batman didn't admitted, but he stood up.

"He's clean. Manhunter found a failsafe planted in his mind, to shut him down, but he already removed."

"Wait… A failsafe? To shut him down?"

"Yes. Two words, that if said by a certain person that we couldn't identify, would put him on a state of coma, of sorts, for a few hours. Like a pause button."

"This is sick." he murmured as they walked the hallways of the Watchtower. "He's not a machine!"

"True. But he's free from it now. And he doesn't have any sort of tracker on him. Also, Manhunter confirmed that the story Robin, Aqualad and Kid Flash told us yesterday is completely true."

"So where is he?"

"We put him on one of the rooms here for the night, until we could find a more permanent solution."

"I want to bring him home." Superman declared.

"Are you sure?"

 _No_ , Clark wanted to say. But he was giving the boy the benefit of the doubt, and his daughter a chance to be less lonely.

"Yes." he said instead.

Batman seemed to see right through him, but didn't comment. They stopped on a hallway far away from the main areas of the Watchtower, and his friend turned to him.

"You can talk to him here and take him home afterwards."

"I still have work today. I can pass by here later? Before my patrol, that is."

Batman only nodded once. "As you wish. I can ask Manhunter to help him get ready until you come later while you talk to him."

"I would appreciate that, thanks."

Batman nodded to the door. "He's all yours."

And then he left, leaving Superman on his own against the boy who was probably upset with him – and with reason.

He took a deep breath and a step forward, knocking the door twice.

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 **This one ended up a little bigger than I expected. Oh well.**

 **Again, let me know if you find any errors and I'll edit it.**

 **If you want to be a beta, PM me. ;)**


	3. A Real Talk

**A smaller chapter today, but not less important. ;) Enjoy.**

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 **Chapter 3 – A Real Talk**

Superboy opened the door ten seconds later. His eyebrows shot up when he saw who was at the door, and his eyes went wide. Superman suddenly felt more guilty than anything. The poor boy looked so incredibly surprised... And he shouldn't be.

He was still wearing the tattered uniform from Cadmus, and Clark had to frown at that. They didn't give him anything to wear?

"You're still wearing that?" he asked, a little irritaded, but not at the boy.

Unfortunately, the boy didn't realized that. He suddenly passed from surprised to offended.

"It's my solar suit." he said, the voice almost a copy of his own too, only younger and a little more angered. He was a little defensive, and Clark realized he failed him again.

He took another deep breath.

"I'm sorry, that's not what I meant," he sighed. "I mean... No one gave you anything proper to wear? Your clothes are torn and dirty."

The boy looked a little less guarded, but shrugged. Superman didn't know what to say about that now, so he changed the topic.

"Can I come in? We need to talk."

Superboy nodded and opened the door a little more, letting him in. He stood awkwardly by the door, even after the boy closed it and went to stay in front of him, by the bed, but still standing.

"I'm sorry," Superman blurted out. "For flying away yesterday, without so much as a proper talk with you. That wasn't very nice."

Superboy's eyes warmed up a little, and he seemed a little more relaxed.

"It's okay," he dismissed the older hero. "You're probably very busy."

"It's not okay," Superman insisted. "I should've treated you better. Can you forgive me?"

The boy looked suprised, but nodded anyway.

"Thank you," the hero breathed, relieved. "Now... I need to talk to you about something else. Something a little more... private."

"And what is it?"

He looked right into the boy's eyes, and saw nothing more than a child trying to understand this new world that he was suddenly in. He took a deep breath and sat on a chair nearby, and Superboy sat on the bed, looking at him warily.

"This is not commom knowledge, and I would like to keep it that way."

 _'Keep my secret, please. Help me keep her safe.',_ was the unspoken plea.

"Sure..." the boy whispered, a little agitaded and uncertain.

"I have a daughter," the hero said, seeing how Superboy's eyes went wide again, his heartbeat stopping for a minute and then racing. "I had her when I was on my twenties, and she's almost sixteen now."

He stopped, trying to understand Superboy's reaction. He looked surprised, shocked and... rejected?

"I see." he said, his voice low and rough suddenly. He cleaned his throat and talked again, but he looked stiff. "So you don't have time or space for me. I understand. That's not what I want..."

He could see the conflict in the boy's eyes. Could _hear it_ in his heartbeat. He was quick to stop the boys assumptions, though.

"That's not what I'm saying, Superboy," he spoke calmly, and the boy look at him confused. "I said that to you because she wants to meet you, and I thought you should know about her before that."

He looked nervous now, and Clark decided to keep talking, until he had said everything, or the boy would have a heart attack. Probably.

"After I left Washington yesterday, I went home. She was still awake and I talked to her. She was mad that I hadn't brought you with me then," he smiled nervously, looking away from the boy for one moment. "We talked, and that's when I realized how badly I had treated you. That's why I am here now. I wanted to apologize. And as my daughter, I want to meet you. I want to get to know you. I... I want to be your mentor, if you still want that."

Superboy looked like a gaping fish, and Superman was so nervous he couldn't do anything but stare, waiting for the boy to answer.

"I... don't know if..."

"She and I would love that." he interrupted, trying to convince himself too. "She always wanted a brother. And you both can easily pass by twins."

Superboy blinked. Several times. Confusion in every one of his features.

"You want to take me to your home?" he asked, seemingly recovering his talking skills.

"Yes."

"And mentor me?"

"Yes."

The boy looked unsure, and Clark wondered if he really had made that bad of a first impression to get a reaction like this from his request.

"You only have to come with me to our place if you want," he added, trying to make the boy more comfortable. "I'll still be you mentor regardless, and I'll train with you, teach everything I can so you can learn more about your powers and how to use them. Since you want to stay with us heroes, I will help you. Gladly."

Clark found that this was true. Even if the boy didn't accept going to his place, he would be happy to teach him about his powers and other things in general. Maybe having a boy to take care wasn't on his plans, but now that Superboy was here, he could not see anyone else having what it was needed to take care for the boy properly. It had to be him.

Superboy did seemed relaxed by the idea that going to Superman's house was optional, but the hero was hoping he would accept. Not many people in the League knew Superman had a daughter, and it would be difficult to prevent Claire from coming to the Watchtower to meet Superboy if he didn't come with him to Metropolis.

"I think..." Superboy interrupted his musings with a small voice. "I think I want to go."

Superman gave him a warm and genuine smile.

"That's wonderful."

The boy smiled back, and suddenly Clark realized that he _could_ do this. He could be a father for this kid. Because despite his physical appearance, he was less than a day old, and despite his knowlegde, he didn't know a lot of things. Clark could teach him. Claire would help, too, happily.

"So..."

"I need to get back to work," Superman said, giving the boy a small smile. "So I can't take you home now. But as soon as I'm out, I'll come back and we'll go, okay?"

"Ok."

"Martian Manhunter will help you pack and I'll come pick you up by the end of the day." he said, getting up, the boy mimicking him.

"Sounds great."

He made a move to leave, but hesitated at the open door, looking at Superboy, who was fidgeting. He made his mind right after hearing his beloved daughter's voice in his head, screaming at him: ' _just hug him!'._

And that's what he did, surprising the boy completely. After a few seconds, he let go, smiling.

"Thank you for the second chance."

"I can tell you the same," the boy said, a smile in his lips and the blue eyes shining a little.

Clark waved, and then went in the direction of the zeta tubes, ready to hear the deafening scream of delight when he called Claire to tell her she had just won a brother.

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 **Aw, so they're in good terms now. Sorta.** **Next chapter we have Superboy's POV! ;)**

 **Answering a Guest review: I intend to update at least twice a week, but since I have other projects going on, I can only promise one chapter weekly. Either way, the day is very much random, depending on where I am at writing the story.**

 **Thank you for the reviews! Keep 'em coming, and as usual: tell me if you find any errors and I'll edit. :)**


	4. Theories

**A big thank you to everyone who's reading, following and putting the story on favorites. This makes me a very happy writer. *-***

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 **Chapter 4 - Theories**

He could _never_ , even if he lived a million years, imagine such a thing.

 _Superman has a daughter_.

His mind kept going back to this one little phrase, who seemed to have changed how the world moved around him. True he didn't really lived that long – it was barely a day after he woke up to this life –, but even if he had, his mind would have some trouble processing the idea, he was sure.

Superman had left his temporary room a few minutes ago. Superboy decided to sit on his bed, with nothing else to do until he came back later to take him to his place and meet his daughter.

 _If he comes_ , his mind kept telling him. He tried not to think of the possibility of the hero changing his mind.

He would never admit to anyone, but being rejected by Superman the night before had hurt. A lot. He had to swallow a huge lump that formed in his throat at the retreating form of his DNA donor _,_ and was left wandering if he had done something wrong. If he was that disgusting, such an abomination that even _Superman_ – the most welcoming and warm hero ever – could not even stand to _look_ at him.

He supposed he would have to thank his new friends later. If they could be called that. Superboy wasn't sure. This new world was still very new, very strange to him. But he remembered the little conversation the four of them had the night before, after Superman left and Batman was still talking with a few Leaguers about what to do with them.

.

 _ **~ The night before ~**_

He didnt have to say anything. The other boys knew exactly what he was thinking.

"Don't worry, Supey." said Kid Flash, in a warm tone. "He'll come around."

"Yeah," Robin. "He's just surprised. He would never expect a clone."

"I am sure Superman will talk to you soon," said Aqualad. "it is not like him to reject someone just because of their origins."

He turned his eyes from the sky – Superman's form long gone – and looked at the three. They were looking sympathetic, with small smiles on their lips.

"Thank you." he said simply, not knowing what else could be said.

They nodded, and Aqualad put a hand on his shoulder.

"Anytime, my new friend." he assured, Robin and Kid Flash vocalizing their support, too.

 _ **.**_

 _ **~ Present Time ~**_

He supposed he would have to thank the three of them for the support, once he saw them again. _If_ he saw them again. Batman was pretty mad after the events, and even after Robin's suggestion that they could do _more_ , he had dismissed them very fast. Superboy didn't know what would happen from now on.

A knock on the door took him out of his musings, and he got up and went to the door. Martian Manhunter was there, no expression in his green skin, but his voice was warm.

"I was told Superman is coming to pick you up later. To take him to his house."

"Yes." he confirmed. "He said he was coming after his work."

Superboy still had no idea what he meant by that. Didn't Superman was a hero? Or could it be that 'work' meant simply going around the world, helping people?

"Very well. Here." Manhunter gave him a bag. "There's a few clothes in there. I am not sure if they will fit you properly, but it will be better than your tattered uniform."

Superboy blinked twice.

"You may use the bag to put anything you want to take with you."

"But I don't have anything." he said.

"Anything from this room may be considered yours, Superboy. Please be free to take it with you, if you want." Manhunter gave him a small smile.

He blinked again, but nodded anyway. Manhunter said he if need anything, to call him over the intercom in the room, and then left him alone.

He closed the door after the martian, and then looked around. There wasn't anything here he wanted to take, really. He didn't know what to do with half of it. But his suit... He somehow was hesitant to leave behind.

He started to take it off, being careful not to rip it any further. It was the only thing that was actually _his_ , and he didn't want to lose it.

He's naked and sets his suit on the bed, picking up the clothes in the bag. He dresses slowly, realizing all of them are a little big for him, but he's not really bothered by that. The well-worn jeans and t-shirt are cozy and comfortable, and he likes the feeling of it against his bare skin.

As soon as he's ready, putting the too big shoes too, he puts the solar suit in the bag, and looking around, he decides he will take the magazine he was looking at earlier too. It's interesting enough, and he didn't finished reading.

And then, he's ready. And it only passed fifty minutes since Superman left. He sighs and sits in his bed, his mind going to these words again.

 _Superman has a daughter._

How is she like?, he wonders. Does she looks like her father? Like her mother? Who is her mother, anyway? Is Superman married? He didn't mentioned a wife, so Superboy thinks it's safe to assume the mother is not present, or at least, doesn't live with them.

He imagines if she's nice. Superman said she wants to meet him. Does she really? Or she justs wants to see the abomination that someone made of her father? He shivers at this particular thought.

He can't think too much about her. He didn't even knew she existed a couple of hours ago. Superman made sound like she's nice and really wants to see him, so he will settle for his donor's words for now.

Sighing, realizing he won't do any good to himself thinking too hard about Superman's motives and his daughter's character, he sits in his bed and turns on the television, trying to focus on anything other than his thoughts.

He is so distracted by the TV that he doesn't see the time passing, and soon... it's time.

There is a knock on his door, and he gets up to open it.

Superman is there, a smile in his lips and uncertainty in his eyes.

"Ready to go?"

Superboy just nods, and goes to turn off the TV and picks his almost empty bag from the chair.

"Great," the hero says. "Follow me."

Superboy obeys, a small tingling feeling in the pit of his stomach that he's not really sure what it means.

* * *

 **I just want to hug Superboy forever. Am I the only one?**

 **As usual, tell me if you find any errors, so I can fix it and improve my writing. ;)**

 **Next chapter someday next week. :***


	5. Welcome Home, little brother

**Time to see Claire again. Yay! Enjoy the chapter.**

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 **Chapter 5 - Welcome Home, little brother**

Claire was so excited she barely enjoyed the party for Mrs. Anderson. Of course, she said her congratulations, took pictures with her friends and favorite teacher, and so on. But her mind – her superbrain, as GrandMa used to say – was focused on other things, too.

Like her new brother. She couldn't wait to meet him!

True, she was shocked to find out that her father had been cloned, apparently by his enemies, and that demanded further investigation, but the boy chose to be a hero. He helped the others and fled Cadmus, and that _meant_... That she was a big sister now.

It was like a Christmas morning.

Her best friend, Kyle, noticed her distraction, of course.

"What are you so excited about?"

She was eager to tell, but didn't know for sure what kind of story her dad was going to concoct to explain Superboy – who also needed a human name, now that she tought about it – and Kyle didn't know about her. That she was a half-kryptonian, that is.

"Oh, I'm just with some extra energy today."

That usually did the trick, and it wasn't different this time. Kyle let the subject go, and they continued their boring chat about some school work. She was really thinking about how to welcome her new brother home, not algebra.

She had to go somewhere private so she could scream properly when her father called her at lunch time to say he was bringing Superboy home later. Since then, she couldn't, for the life of her, think about something else. She didn't want to, either.

At last, three o'clock came, and she said goodbye to her friends and went straight to her favorite bakery, trying to decide what would be the perfect 'welcome home' cake. She settled for a large one made of vanilla and chocolate, decorated with more chocolate. She loved, and was pretty sure her new brother would, too.

She went home with a bounce on her step, humming happily as she went. As soon as her feet crossed the front door of their three-bedroom apartment, she set the cake in the table and went for a change of clothes. Soon she was on some comfortable shorts and t-shirt, and grabbed a lot of paper, putting them together so she could make a big sign. With the paper all glued together, she picked some markers and started to draw and write on the sign, layed out in the floor of the living room.

It took her some time to figure it out what to say exactly, so it wouldn't be awkward, but finally she had a decent welcoming sign, and then she started to strap it on the hallway, right in view from who entered the door.

With that done, she went to check the fridge for some soda and other things they could need for the welcoming party. She could always go to the grocery shop nearby and buy something missing, but she wanted to be home when her father and Superboy arrived, so she didn't want to do things last minute and ending up not being there when they arrived.

When everything was done, she looked at the clock and let out a bored whine, seeing that it was still one hour until her father was out of work. And she was so excited! The wait would take forever...

Like a lightbulb, an idea popped into her mind, and she took the supplies she needed and went straight to the guest room, starting to cleaning it up and making it her new brother's, a big smile on her lips all the time.

~.~

 **Recognized: Superman; 01. Superboy; B-04.**

Realizing he had a register in the zeta tubes made Superboy feel... good. He didn't know exactly why.

They got out in some alley in what looked like Metropolis, and after a quick glance to the sidewalks, Superman turned to look at him.

"So, we can't just go to my place with me dressed like this." he said.

Superboy nodded, understanding it would be too much of a giveaway people seeing Superman getting into his apartment. Superman took this as his cue, and sped to some place in the back of the alley, reemerging two seconds later, dressed in normal clothes... and wearing glasses. Confusion took Superboy's features as he spoke.

"Why do you need glasses?"

He could understand – sort of – the plain suit and tie, but the glasses were a mistery to him.

Superman only smiled, like he had heard that before.

"It's part of my disguise."

He still didn't understand. But before he could ask, Superman talked again.

"Come. Follow me. My daughter is probably dying of excitement by now."

He followed the disguised hero for a couple of blocks, before Superman took a set of keys out of his pocket and opened the front door, waving and smiling to the guard behind the entrance.

"Hey Mr. Willis!"

"Hello Mr. Kent! Here's your mail."

The middle aged man gave Superboy's DNA donor some papers, that Superboy recognized from his implanted knowlegde as bills and letters. Superman thanked the man, and before the doorman could ask about him, Superman ushered Superboy to walk. He did so, happily. He had no idea of what to do with new people – especially civilians.

They got into an elevator in the main building, and after entering, Superman pressed the last number – 18.

"I live in one of the highest apartments. It's easier to sneak out undetected if I need to fly away to save someone." he said.

Superboy nodded, understanding the logic. The silence stretched while the numbers increased slowly, at least until Superman broke it.

"I should warn you... My daughter can be very..." he seemed at a loss of words, and Superboy didn't know what to do – for the millionth time that day.

Superman sighed and smiled for him.

"She's a very nice girl. Very smart, very passionate. She will love you, and I just want you to know that."

Superboy blinked and nodded.

The doors of the elevator opened, and they stepped outside. Superboy noticed three doors at the hallway, all with numbers, probably three apartments.

"You're awfully quiet." Superman said after they walked til the last apartment in the hallway: _1803_. He set the key in the locker, but looked at him before opening it.

"I just... don't know what to say." he admitted, even if he didn't wanted to show weakness in front of Superman, because... What if he changed his mind about him?

Superman smiled again. His eyes were warm, and Superboy noticed that there wasn't any of his uncertainty from before. If anything, Superman looked... excited?

"Then lets meet your new sister." he said, opening the door before he could reply.

He got inside and Superboy followed, Superman closing the door behind him while he took in the sight that greeted him.

It was the first thing he noticed: the big paper sign hanging between the walls, colored and bright. The words: " _Welcome home, little brother!_ " were written in big and curly feminine handwriting, the rest of the sign decorated with hearts from different sizes and colors; a lot of smiley faces, and the S symbol of Superman covered every other part of the sign.

It made something in his heart, seeing this. Something warm and unfamiliar, something that made him take a deep breath, because suddenly there wasn't enough air. He didn't know what was happening, but... he liked the feeling.

"Claire?" Superman's voice echoed in the space, the hero going further in the apartment, followed closely by the boy. "We're home, sweetie!"

Suddenly there was a door being opened, and before he could register it, there was a girl standing right in front of him.

"Oh my God, you're here!" she squeaked, making Superboy take a step back in surprise.

Superman's laugh filled the space.

"Honey, let him breathe."

"But I..."

He drowned the words she said, mostly because he was occupied taking the sight.

Superman's daughter was there. In the flesh. Claire – as her father had called her – was like a female version of her father. She had a jet black hair that went until her shoulders, the striking blue eyes and well designed nose, not too big or too small. Her lips were stretched in a big, excited smile, looking at Superboy with such _happiness_ that he didn't know what to say.

"Hm... Hi." he said after it became clear that they were waiting for him to say something.

Her smile became impossibly wider.

"Oh my God, you're adorable! I love you already." she squeaked and then went to hug him, fiercely, strongely.

She hugged him so tight that he was sure now – she had powers too. Impossible not too. He tentatively put his arms around her, awkwardly, and she tightened her grip.

"Welcome home." she whispered, and the warm feeling on his chest intensified.

"Thank you." he heard himself whispering.

She pulled back and was still smiling.

"Come, let me show you your room. I was setting some stuff for you there, I hope you like it."

And that was it. No funny looks, no questions. She just... Was honestly happy and excited that he was there.

So he couldn't bring himself to do anything else than follow her, wholeheartedly and happily.

* * *

 **Yay! Conner - ahem, I meant Superboy, haha - is home now, and next chapter will be all about him and his new sister.**

 **Tell me what you think so far, I love seeing your reactions to this story. :)**

 **Answering a Guest review: Claire has powers, although not all of her father's - she's still a teenager. The reason of why she is not a hero and known by people will eventually be revealed. ;)**

 **As usual, tell me if you find any errors! :***


	6. Sibling Bonding

**Chapter 6 – Sibling Bonding**

Clark could not hide his smile. His decision to bring Superboy home never seemed so right. His daughter was dragging Superboy by the hand to the guest room, and he noticed that she had cleaned it up, changing a little bit the decoration and making the room more comfortable.

"So... what do you think?" she asked excitedly when they got in. Her eyes were shining and Superboy looked around, still a little uneasy.

"Hm... Looks nice."

"It's your room now." Clark said, sending a grateful look to Claire for having prepared the room beforehand. "We'll probably need to go out somewhere soon so we can buy a few things for you, including new clothes that can actually fit you."

Claire smiled. "Yes! A shopping trip. It will be awesome!"

Superboy smiled for her, but looked a little unsure whether or not getting in the room. Before Clark could say anything, though, he heard the distinctive sound of a blaring siren and gunshots and screams. He sighed.

"There's a car chase downtown. I have to get there." he said, and then put a hand on Superboy's shoulder. "Claire will make you company while I go out, ok? I'll be back soon, I hope."

Superboy only nodded.

"Be safe, dad." Claire said.

He smiled for them, changing to his uniform and flying away through the window.

~.~

After her dad left, Claire insisted with Superboy that he could take a shower and change clothes. He didn't have anything proper to wear, so Claire picked up a few of her dad's old clothes and put them on Superboy's bed so he could change. She could always make some adjustments, if needed.

Going back to the kitchen, she decided to start making dinner. The cake would probably be served later, when her dad was back and they had a proper dinner, so she put the cake aside and started picking up ingredients.

Superboy appeared in the kitchen not much time after, standing a little awkwardly in the door frame that divided the kitchen from the dinner room.

"Hey!" she said, trying to make him more comfortable. Poor boy was all nerves so far, and Claire wanted him to lighten up a little.

"Hey." he answered.

"How was your shower?" she said, half her body almost inside the fridge picking things for dinner.

"Nice." he said.

She emerged from the fridge and smiled for him.

"You're not a guy of many words, are you?"

He cleaned his throat. "It's just... Too weird."

"What is?"

"This." he pointed around. "Me at Superman's house, watching his daughter cooking."

She laughed a little.

"Yeah. I bet the fact that he had a daughter made your brain freeze for a few seconds."

She saw the smallest of smiles in his lips, and his eyes were dancing with amusement.

"Yeah, it did. I came here still expecting it to be a joke."

Claire laughed a little more.

"Well, it's not." she said, starting to cut onions. "It's just not public information."

He nodded, and pointed to the other vegetables.

"Do you want help?"

She stopped cutting the onion and looked at him. "Do you know how to cook?"

He seemed embarrassed, now.

"Well, not really, but..."

She smiled. "Great! I can teach you!"

He looked at her with surprise in his eyes, and also excitement. She picked up another knife and gave him a few tomatoes to cut, showing him how to do it.

Superboy was a fast learner. He soon was cutting the vegetables as fast as her, helping her with the spaghetti carbonara which she decided for dinner. They didn't talked much, but she realized that his posture became a little more relaxed, more light. Like he was really enjoying being there.

Finally, when there was nothing left to do but to wait a few minutes, she started setting up the table with his help. That's when he decided to ask a few things.

"So... Superman has a job?" he seemed honestly confused.

"Yes. He's a reporter at the Daily Planet. And you can call him 'dad' or by his name if you want. And if we're home and he's not in costume." she smiled.

He looked a little more confused.

"His name? But... It's Superman. His name, I mean."

Claire suddenly stopped putting the silverware on the table and looked at him. Superboy seemed completely and honestly lost about this.

"Well..." she started explaining. "Most heroes have secret identities. The hero name is a name they invented so they can fight crime without being recognized. It's also why they wear costumes."

He seemed intrigued. "Really? Cadmus didn't put anything about that in my education."

Claire fought the scowl that she wanted to make by hearing about his 'education'.

"Well, it's a thing." she continued. "So the heroes names aren't actually their real names, you know? They are not their birth names."

Superboy seemed to think for a second before asking, timidly.

"So... What is Superman's name?"

"Clark Kent." she said, smiling for him. "You can't tell anyone this. Secret identities exist to protect the heroes' families and friends from harm. And to let the heroes live somewhat normal lives when they are not saving people."

He frowned, but nodded his consent. "It's a weird concept."

Claire laughed a little. "It's an important concept."

He smiled for her, and they kept talking casually until Superman came flying through the window.

"Hey dad!" she waved. "How was patrol?"

"Nothing big." he shrugged. "I'll take a shower and join you two for dinner."

And then he was gone. Superboy blinked.

"He just used his superspeed, right?"

"Yeah," Claire laughed. "he normally does that when he's really hungry. Now come on, let's put the food in the table too."

~.~

Dinner went very well. Clark and Claire were amazing people, and Superboy saw himself smiling to them in more than one occasion. There were still some awkwardness in his and Super- _Clark_ 's communication, but he supposed it should pass soon. He was his clone, after all. Clark had to get used to the idea.

He helped Claire with the dishes, while Clark started writing something on his laptop – a story for the Daily Planet, he said, and Superboy still couldn't believe Superman was a reporter – and they went into a peaceful pace with an amicable silence.

Soon after, Claire ran to her dad's room and picked a few clothes for him, and Superboy had to put every single one of them, because Claire made her job to adjust the clothes so they could fit him properly, until they could go out in the weekend and make that 'shopping trip' – for which Claire was particularly excited about.

When she finished making marks on where the clothes would be needing adjustments, it was almost eleven pm, and Sup-Clark told them to go to sleep.

"But I'm not even tired!" Claire complained.

"But you have school tomorrow morning, Claire." Clark said, stern but not unkindly. "You should rest."

She made a pouting face that made Superboy laugh, and then she was smiling at him. Getting up from the couch, she went to give him a hug and a kiss on his cheek.

"I'm really happy you're here, Superboy." then she frowned. "We really need a name for you."

He didn't know why he would need another name, but didn't said anything. She shook her head and smiled at him again.

"Anyhow... Good night, little bro." she took the clothes and her sewing kit with her for her bedroom, that was right in front of his.

Awkwardly, he stood and saw that Clark was looking at him.

"I'm happy you're here too, you know." the hero said. "I'm sorry I didn't brought you here yesterday."

He smiled, honestly.

"It's okay. I'm here now and we can start over. And... Thank you for giving me an opportunity."

"You are very welcome." Clark said, and then, "Good night."

He mumbled a 'good night' back, and went to his new bedroom, that was still very bare, but he had the feeling Claire would help him fill, and the thought of having her supporting him and helping him adjust to this new life made him lay on his bed with a smile on his lips.

* * *

 **Awn. I really liked writing this chapter.**

 **As usual, tell me if you find any errors so I can fix it and improve my writing. If you want to be a beta, PM me.**

 **Next chapter is the last one of this story, but don't worry! I have a lot of ideas for this AU, and there will be more stories very soon! :)**

 **Now, tell me what you think! :***


	7. We Are Family

**Chapter 7 - We Are Family**

Of course once his head hit the pillow, Superboy couldn't sleep. He had problems sleeping at the Watchtower the day before, never having slept on a bed. It was weird, sleeping laying down and not up, but he had managed a couple of hours last night.

Now, however, he was too awake. The night with the Kents had left him with a lot to think – good things, fortunately. Claire was nothing like he imagined when he first heard about her. He thought she was going to be a little wary of him, maybe even ignore him like her father did at first, but that wasn't what had happened. Claire was nothing but warm, welcoming and happy that he was there – calling him 'little brother' and a lot of affectionate names, and also planning _things to do_ with him.

The feeling of being wanted swarmed him and left him being glad that Robin, Aqualad and Kid Flash had disobeyed Batman's direct orders, no matter how much trouble they could get for that. He couldn't regret being freed, couldn't regret the choice of leaving Cadmus and its sterile labs and halls. He was no more a weapon, designed to end enemies of his creators; he was Superboy. He was his own; he was wanted by Claire, wanted by Clark now.

Of course, that also made him a little nervous. He had very little information about the world he was in. Cadmus' education had focused on history of Earth, and knowledge about the heroes of the Justice League, and a few other useful things, like driving, reading, writing and so on. But practical knowledge... Like the thing about 'secret identities' and other things he heard Clark and Claire talking at dinner... He had no clue.

And what if his lack of knowledge of these things made him unfit? What if those things were too much, and Clark and Claire ended up deciding they didn't want him for that? What if he wasn't enough?

That made him restless. He didn't know what to do, and his brain was going a thousand miles per minute trying to find answers he didn't have.

With his superior hearing, he heard when Claire turned off the light of her bedroom and went to bed. Heard when her heartbeat slowed and she fell into blissful sleep. He heard when Clark got out through the window again, his cape fluttering behind him. He also heard when he got back, something like thirty minutes later, locked the door and windows and went for another shower, and then slept. The house was silent, and Superboy was never more awake.

He decided he would get out for a little air. His bedroom was too new, too unfamiliar, and he was too awake to sleep now, anyway.

He got up, getting out of his bedroom as silently as possible. The fact that all the people in this place has super hearing was tricky, he knew he could wake them with the littlest of noises.

Fortunately, that didn't happen, and Superboy went to the kitchen for a glass of water. He wasn't really thirsty, but something in the back of his mind told him that usually when people had trouble sleeping, a glass of water or warm milk were useful. It wasn't, he realized as soon as he finished the glass.

"Trouble sleeping?" a female voice interrupted his thoughts about trying milk.

He turned to see Claire in her pajamas, smiling to him as she poured a glass of milk for herself.

"Actually, yes..." he admitted, deciding to be honest. "It's weird sleeping laying down."

"I see." she smiled. "I woke up with dad's snores, for some reason, and now I can't sleep either. We could watch a little TV, maybe? Or talk with each other. Maybe that'll help us."

He nodded, and they went to the living room after Claire served them both with a glass of warm milk, making Superboy smile a bit. At least he knew about that.

They sat in the couch, and he thought she was going to turn on the TV, but instead, she turned to look at him.

"I have to be honest with you."

She was serious, and something on her eyes made him uneasy all of a sudden.

"Okay..."

She took a deep breath before talking.

"I always wanted a brother. Since I was a little girl. It's kinda hard to grow up as an only child." she smiled a bit. "But I was a miracle. Dad's DNA is too different from humans' to actually have a child, but something on my mother's DNA was mutated, which allowed for her to conceive from him." she explained slowly. "I shouldn't exist, basically. So since I was a kid and dad told me this, I knew it was impossible for me to have siblings. And that always made me kinda sad."

He stood perfectly still, listening to her story without so much as flinching. Claire looked pained for some reason.

"Dad always knew this, and it breaks my heart to think of how many times he had to ignore my pleas just because he couldn't do anything about it. Also, he's 37 by now..." she sighed, and then looked at him. "When he told me he had a clone, a sixteen year old clone, you know what my first thought was?"

He shook his head, honestly wanting to know.

"I was happy." she shrugged. "My dad was telling me that his enemies had somehow cloned him, with evil purposes, and I was happy. In my mind, all I could think of was that I finally had a brother. Someone besides my father to call 'family', and that..." she smiled. "That feeling was amazing."

"I could be evil." Superboy said, slowly and his voice very low. "I could be on the side of the villains."

"Yes, you could." she admitted. "That didn't mattered to me at the time, even more so when dad told me you chose to leave the lab."

"What if I hadn't left?" he asked, afraid of the answer.

She smiled again. "It wouldn't have mattered. Of course, you would never be here now, but the fact that I had a brother somewhere... That would've made my day. And I assure you, I would find a way of finding you and bringing you home, convince you to come to the side of the heroes, so to speak." she laughed a little.

"You really wanted a sibling, then." Superboy said, smiling at her admission.

"Yes. What I'm trying to say to you now is that you're not alone anymore. I don't care what happens from now on, I want you to know this:" she took his hands on hers, tightly, before saying the rest. "I love you. You are family, and I'll always be here for you, to help you in everything I can and support you in everything I can't help you with. I'm _on your side_ , Superboy, and nothing and no one can change this, understand?"

Suddenly, Superboy's thoughts of not being enough went away. Here she was, saying exactly what he needed to hear, even though he hadn't known he needed to hear this. He smiled for her, feeling a lot better.

"I do. Thank you, Claire."

She smiled largely. "You're welcome, little brother."

They laughed together, and she kept holding his hands. He didn't let go either.

"So, I guess we could be twins." she said. "I'm about to make sixteen in August, and you are sixteen, so..."

"Being twins sounds wonderful." Superboy admitted, smiling for his sister.

"Yeah, it does." another voice said.

They both turned to see Superman – Clark, he has to get used to his name – standing, leaning on the wall, dressed only with sweat pants, and looking at them both with pride in his eyes. Smiling.

Superboy's chest constricted, but in a very, very good way.

"I have twins now." He said.

"Yes dad." Claire laughed. "You do. Now it's two against one."

He laughed at that.

"Why does it have to be against? I can't with both of you. We can always get to an agreement."

"Yeah, we can." Superboy said, before he even knew what he was talking. "We're family... Right?"

Clark and Claire looked at him with watery eyes, before Clark ended the silence.

"Yes... We're family."

The feeling on his chest only intensified at that, and Superboy was really, really glad he was there in that moment.

"Now, we all need to sleep." Clark said, after clearing his throat.

Claire whined, but agreed. They all went to their respective rooms, and after a hug from Clark and Claire, Superboy thought that he didn't have to wonder about his future with the Kents anymore.

It was obvious as the sun: they wanted him, and it didn't matter where he was from, and how he came to be. He was family, and that was the only thing they needed to accept him.

With this thoughts, Superboy didn't have any trouble sleeping after he went to bed again. His mind kept remembering him: no matter what would happen next, he had at least one person on his side, one person that could help him with anything.

If anything went wrong, at least, from now on, he would always have his big sister.

 **\- The End -**

* * *

 **To the anon who left a comment saying that by canon, Claire should be 12: I thought about that, but my idea is basically having them as 'twins', so that wouldn't work. So I'm ignoring canon, and making it like this: Clark became Superman at 25 (Claire was 4), and now he is 37 (as said in the chapter). Just a little different from canon, but still. This is a AU for a reason. ;)**

* * *

 **Like I said before, this is the last chapte** **r of THIS STORY. There will be more. I have ideas for a lot of stories in this AU. The next one it's called "Identity" and it's a two-shot, that should be out by Tuesday, so you can wait for that. ;)**

 **As usual, tell me what you think of the chapter, and if you find any errors, tell me so I can edit and improve my writing.**

 **I loved writing this, and I can't wait to get into this universe a little more, so... See you soon!**


	8. Sequel Warning

Hey!

For those of you who want to keep reading more about this AU, the sequel is up!

It's called " _ **Identity**_ " and it can be found on my profile (damn you ff for not letting me put links in here).

Anyway, I hope I see you there. ;)

xo


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